2011 BMW ActiveHybrid 7

Staring down the barrel at tough upcoming high fuel-mileage standards, automakers are scrambling for solutions. Smaller cars. Diesels. Electric cars. And, of course, hybrids. BMW already has one in the form of the X6 ActiveHybrid, a real hybrid that can run on pure electric power. Now Munich adds the ActiveHybrid 7, a mild hybrid that never goes into electric-only mode, but is claimed to offer 15-17 percent better fuel economy than BMW's 750i.

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Here's how it works: Behind the 440-bhp turbo V-8 is a 3-phase electric motor attached to the engine's crankshaft. Combined they put 455 bhp and 515 lb-ft of torque into the 8-speed automatic aft of the electric motor. Power for the motor comes from a lithium-ion battery that takes up a relatively small corner of the trunk.

The basics of the hybrid work–mainly the battery technology–was done by BMW in cooperation with Mercedes, but while Mercedes' S400 is optimized for fuel economy, BMW went for performance...which is not unexpected.

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So nail the pedal to the mat and the V-8 and motor combine to launch the big Bimmer to 60 mph in just 4.7 seconds. You don't exactly feel socially responsible doing it...but it sure is fun.

However I was in a car with two other liberals, so we also went for max fuel economy on our longish drive. You can imagine what we were discussing, the BMW gliding along at an average of 66 mph and 29.4 mpg...with the electric a/c on. I later did some short-term runs in the car to check city driving and managed to stay up near 30 mpg if I just took a little care.

Other than a slight sense of the engine dying as it went into stop mode at stoplights, the transitions when the electric power is added or ended are seamless.

Impressive, but pricey, at $102,300 for the short-wheelbase ActiveHybrid 7 and $106,200 with the longer wheelbase, about a $21,000 bump from the 750 versions.